Quasi-statically Planned Self-posture Changeability For Link System

With a proper combination of compliant and positioncontrolled joints, a link yystem cm change its posture with keeping contuct between link system and environment. This motion is so-called Self-Posture Changing Motion {SPCM). This paper first discusses se\-eral key technologies to realize a SPCM with defining it in a general form available for plane contact as well UF point contact. A SPCM can be applied for detecting an approximate contact point between a 2-0 /ink system and an unknown object. The second goal of this puper is to explore a scheme capable of providing a clowrpoint to the object's surface. In order to evaluate a coniputing scheme, Degree-of-Approxiilzation (I1.O.A) is newly introduced. This is defined as the distance between a computed point and the nearest point oi'er the object's surfuce. We finally proposes a scheme which improves D.0.A and provides an aact contact point not only for a sharp-edged object but also for a constant curved object.